The long term goal of this research work is to gain a better understanding of the molecular mechanism of regulation of protein synthesis initiation in red blood cells and the roles of different factors in this process. In this research, we plan to purify the peptide chain initiation factors from rabbit reticulocytes and study their precise roles in specific steps in peptide chain initiation. We will prepare antibodies against the homogeneous factors. Several peptide chain initiation factors such as Co-eIF-2B, Co-eIF-2C and sRF are complex proteins and are composed of multiple polypeptides. We plan to prepare monoclonal antibodies against the active polypeptide component(s) in these complex proteins. We will use the antibodies in studies of protein synthesis in reticulocyte lysates and also in preparations of immuno-affinity columns for further purification of the factors. We will also compare the characteristics of the peptide chain initiation factors and also the overall mechanism for peptide chain initiation in different eukaryotic cells such as rat liver and wheat germ.